Main Stem Snake River
MAIN STEM SNAKE RIVER
ReportOCT 21 — 28, 2026
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Flow
2330CFS
SNAKE RIVER NR BLACKFOOT ID
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Water Temp
56.3°F
Updated 2026-10-20
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Weather
43–71°F
Partly Cloudy then Slight Chance Light Rain
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Reported By
Bruce Staples
On the water
Brown trout are actively migrating to spawning areas throughout the Main Stem Snake River, with low flows above American Falls Reservoir opening up widespread safe wading and all boat launches above Tilden Bridge. Below the dam, flows are running around 3,700 cfs — ideal for floating but dangerous for wading.
From the ShopBruce Staples · October 21, 2026
Outflow has dropped from American Falls Reservoir as irrigation needs diminish. Widespread safe wading locations are present in the river above the reservoir because of the low flow. All boat launches above the Tilden Bridge are open.
Brown trout are migrating to spawning areas throughout the river. Streamer and woolly bugger patterns on sink tip or full sinking lines with stout leaders are always the best producers. Evenings, early mornings, and stormy conditions (like last weekend) are the best times to fish for them.
Flow below American Falls Dam is about 3,700 cfs, so wading there remains dangerous but is ideal for boating.
What's Working — Hot Flies
Hatch Chart
| Insect | Size | Activity | Prime Time |
|---|---|---|---|
| Brown Trout Spawn | N/A | Peak migration to spawning areas throughout the river | All day — best early morning, evening, and overcast/stormy |
| Streamers / Baitfish | #4–6 | Aggressive takes from pre-spawn and staging browns | Early morning and evening |
| Woolly Bugger / Leech | #6–14 | Consistent producer on sink tip and full sinking lines | Low-light periods and stormy conditions |
Best Time Window
- EARLY MORNING (first light to 9 AM): Prime streamer window — swing and strip woolly buggers and sculpin patterns through staging runs before the sun hits the water.
- EVENING (2 hours before dark to last light): The other top low-light window Madison called out — work the deeper seams and tailouts with sinking lines for migrating browns.
- STORMY / OVERCAST CONDITIONS (any time of day): Cloudy skies and unsettled weather trigger aggressive streamer takes; don't stay off the water just because the forecast looks rough.
Guide's Tip
From the benchRun a full sinking or sink tip line with a stout leader — this is not a time for light tippet or floating lines. Madison notes that evenings, early mornings, and stormy conditions are the prime windows, so plan your day around those low-light periods. If you're looking for a classic woolly bugger not listed in our catalog, any dark or olive bugger in #6–10 will fit the bill — just get it deep and strip it slow through the runs where browns are staging.
Main Species
Brown Trout
Rainbow Trout
Yellowstone Cutthroat Trout
